Ocean controversy

Ocean fertilization is one of the methods being considered to deal with rising levels of carbon dioxide and associated climate change.

Photo: Stuart Chape

The method, which is highly controversial, involves putting nutrients, like iron, into the ocean to stimulate the growth of phytoplankton.

The theory is that this phytoplankton will absorb carbon from the sea, then sink down to the seabed, where it will remain and effectively remove the carbon from the atmosphere.

“Ocean fertilization has been touted as an exciting prospect for the carbon trading market but it needs a solid scientific basis to move forward,” says Gabriel Grimsditch, of IUCN’s Global Marine Programme.

“At the moment the effects of large-scale geo-engineering like this are unknown and we may not be able to reverse them,” he adds.

Some companies want to start researching ocean fertilization and to fund it they want to sell carbon offsets.

IUCN, however, says it is too early to start selling such offsets and companies should wait until environmentally-responsible studies have been carried out.

“To get fertilization credits on the voluntary carbon market, the public should have confidence that the technology is safe, effective and verifiable,” says Kristina Gjerde, IUCN’s High Seas Policy Advisor. “It is important to ensure that any research done to study ocean fertilization is of high quality, that the data are open and reviewed scientifically, and that environmental impact assessments are conducted.”